Heretofore, such as shown in U.S. Pat. No. 5,238,021 dated Aug. 24, 1993, diaphragm operated regulator valves have been utilized to regulate the flow of compressed gas applied to a gas blanket on top of liquids in a storage tank and to other low pressure applications. The gas is normally a non-flammable gas, such as nitrogen. The diaphragm actuator in the '021 patent is relatively large and sometimes it is difficult to maintain a very low gas pressure less than about 0.10 psi in the gas blanket with a large diaphragm. For example, the regulator valve as shown in U.S. Pat. No. 5,238,021 if adapted for very low fluid pressures such as 1/2 inch we would require a relatively large diameter diaphragm housing or case which would not be suitable in some applications.
It is desirable that a diaphragm operated regulator valve for maintaining a preset low gas pressure in a storage tank be provided that has a relatively small diameter diaphragm and is particularly effective at gas pressures less than about 0.10 psi or under two inches water column (2" we).